Seven perfect daily moments

Dr Michael Smolensky, director of the chronobiology centre at the University of Texas, says our internal alarm clocks are programmed to go off after seven or eight hours' sleep. With the first signs of daylight, the production of sleep-inducing hormones such as melatonin slows down. This, in turn, raises your body temperature and boosts you into action. Conversely, in the evening (10 to 11pm), heart rate begins to slow, stress hormones plummet, and a surge of sleep hormones leave you feeling drowsy and ready for bed. By 3-4am, your alertness and body temperature drop to their lowest levels, a few hours before you are programmed to wake up again.

Eat breakfast: 8-9am

Between these hours your metabolism is raring to go and your body will digest food most efficiently. Eating a healthy breakfast every day will help to stave off mid-morning cravings for fatty snacks and can thereby help to keep weight in check, found Professor John Blundell, of Leeds University. "Overnight, your body has been tapping into your fuel stores, especially carbohydrates. A high-carb breakfast optimises your morning mood and concentration, and stops carbohydrate cravings later in the day," says Lyndel Costain, a state-registered dietician and author of the Body Clock Diet (Hamlyn, £9.99).

Work out: 8.15am

Exercise is more likely to boost your mood if performed in the morning, say researchers at Glasgow University. In a study published in the journal Appetite, female subjects took part in an hour-long aerobics class at either 8.15am or 7.15pm. Afterwards, their mood was assessed: the early-bird exercisers were shown to experience a 50% boost to their feeling of wellbeing compared with 20% for those who went to the gym in the evening. The women also said they felt they exerted themselves more in the early classes, although the calories burned were the same. "In the morning the exercise seemed to feel much harder, perhaps because they have woken up, but this means the [psychological] benefit from the exercise is much greater," says Siobhan Higgins, the lecturer in sport science who led the study.

Snack: 10am and 2pm

Try to keep your meal times regular as this enables your body to anticipate food, which allows digestion and metabolism to be more efficient, says Professor Ian MacDonald, of the University of Nottingham's school of biomedical sciences. He found that women who eat at predictable times take in 120 fewer calories overall a day and burn them faster than those who eat haphazardly. Costain agrees. "To keep your blood sugar even and put you in control of your eating, you shouldn't leave more than three or four hours between meals or snacks," she says, recommending rice cakes, fruit and cereals for long-lasting energy bursts.

Use your brain power: 11am

According to Dr Michael Hastings, a chronobiology expert at Cambridge University, brain power peaks before noon, making this the best time to tackle jobs that require cerebral effort. "Your body temperature should also be at optimum level which gives brain efficiency a further boost," he says. Later on brain power has a second surge and long-term memory hits a peak, making mid-afternoon the best time to absorb and remember information. A study of British schoolchildren found that those who listened to a story at 3pm remembered the detail far better than those who heard the same story at 9am.

Eat dinner: 4-7pm

Eating the majority of your food intake (or at least your main meal) between 4pm and 7pm is a controversial approach that could improve your health, according to Dr Mark Mattson, chief of the laboratory of neurosciences at America's National Institute On Ageing. Mattson says the approach mirrors the habits of our cave-dwelling ancestors. In some cases, the blood pressure and general health of his subjects improved. "Our basic metabolism was set up when we were hunter-gatherers," he says. "The pattern would have been a mixture of feast and famine."

Take aspirin: 9.30PM

Smolensky reported in the Journal Of The American Medical Association that your body clock can determine the best time to take medicine. Taking pills at the right time for your body and your illness may boost the medicine's efficacy and minimise side effects - it should be discussed with your doctor, Smolensky says. Taking aspirin before bed can markedly reduce blood pressure, according to a study at the University of Vigo in Spain. Other researchers have shown that osteoarthritis will hit you worst in early evening. Your risk of an asthma attack is 300 times higher between 2am and 6am. And, since our bodies raise blood pressure just before we wake, we are more likely to burst a blood vessel in the early hours.